THE GEOLOGY OP NEW ZEALAND. 
453 
tion of the great Taupo lake, by the subsiding of the land 
to supply the place before occupied by so much ejected 
matter, appears certain ; and further, that this occurred 
at different intervals, for, although the ancient extent of 
the lake was nearly double what it is at present, it seems 
to have become wider and deeper than formerly ; many 
trunks of trees are still visible in its waters, which were 
there when the country was first peopled, and are so well 
known that each bears the name of some ancestor; what 
is here said of Taupo, applies also to all the neighbour- 
ing lakes ; but whilst their basins were thus formed to 
the extent of matter ejected, it is evident that the throes 
of the volcanoes mainly contributed to the elevation of the 
country ; from the sea to the base of Taupo there is a regular 
series of stages, several of which contain plains of different 
elevation, each separated from the other by deep fissures, one 
rising higher than another, until we reach the central plains 
of Tongariro, thence the country gradually slopes to the 
north. But although much of the upheavement of the land 
occurred during the time these volcanoes were in eruption, 
it is also evident that even yet the land is rising ; this must 
be solely attributed to the agency of earthquakes. The 
southern and central parts of the island appear to be the 
principal seat of their action ; and though, in general, the 
shocks are slight, yet, periodically, every five or six years, 
they have been more violent, and attended with more serious 
consequences. 
In the year 1843, Wanganui was the chief centre of volcanic 
movement most of the chimneys in the little settlement were 
thrown down, the church was much injured, and the earth 
opened in parallel fissures, one of which was two feet wide ; 
the cliffs had every appearance of being upheaved a foot on 
one side of the river, whilst the ground on the other, perhaps, 
subsided as much ; the shocks invariably came from the same 
quarter, W.N.W. ; much sulphureous gas also escaped, which 
for a time affected the health of the place ; the movement 
seemed chiefly to follow the course of the river, whose channel 
may be regarded as a fissure on a large scale. 
